Albert D J, Dyson E M, Walsh M L, Gorzalka B B
Physiol Behav. 1987;39(6):693-8. doi: 10.1016/0031-9384(87)90252-6.
Medial hypothalamic lesions or sham lesions were made in castrated adult male rats with subcutaneous implants of testosterone-filled silastic capsules. Seven days following surgery all animals were given a test of defensiveness (reactivity) toward an experimenter. The following day, groups composed of one lesioned male rat, one sham-lesioned male rat, and one intact female rat were placed in large cages. Beginning two weeks later, unfamiliar intruders were introduced into each colony on a weekly basis and the aggressive behavior of the residents recorded. All 12 of the sham-lesioned animals but only 2 of 12 lesioned animals displayed substantial intermale social aggression toward intruders. Analysis of individual elements of intermale social aggression indicated that the lesioned animals were deficient in attack, bite, and piloerection but not in on-top behavior. The deficit in intermale social aggression was not correlated with defensiveness toward the experimenter or body weight of the lesioned animals. It is argued that the medial hypothalamus plays a role in the modulation of intermale social aggression which is independent of its role in modulating defensiveness or testosterone production. These results also demonstrate that intermale social aggression develops even when testosterone levels are held relatively constant by replacing testicular testosterone with an artificial testosterone source.
对阉割成年雄性大鼠进行内侧下丘脑损伤或假损伤，并皮下植入填充睾酮的硅橡胶胶囊。手术后7天，对所有动物进行针对实验者的防御性（反应性）测试。第二天，将由一只损伤雄性大鼠、一只假损伤雄性大鼠和一只完整雌性大鼠组成的组放入大笼子中。从两周后开始，每周向每个群体引入不熟悉的入侵者，并记录居住者的攻击行为。所有12只假损伤动物中，但12只损伤动物中只有2只对入侵者表现出大量雄性间社会攻击行为。对雄性间社会攻击行为的各个要素分析表明，损伤动物在攻击、撕咬和竖毛方面存在缺陷，但在骑跨行为方面没有缺陷。雄性间社会攻击行为的缺陷与损伤动物对实验者的防御性或体重无关。有人认为，内侧下丘脑在调节雄性间社会攻击行为中起作用，这与其在调节防御性或睾酮产生中的作用无关。这些结果还表明，即使通过用人造睾酮源替代睾丸睾酮使睾酮水平保持相对恒定，雄性间社会攻击行为仍会发展。
